SLUDGE CHARACTERIZATION OF STPs IN INDIA

Abstract

Exponential population growth has led to enormous wastewater, necessitating an acute demand for sustainable wastewater treatment facilities. The increase in wastewater facilities creates an unavoidable need for its by-product management. Sewage sludge is a complex mixture of waterborne wastes of municipal and industrial origin. A list of pollutants in sewage includes organic matter, emulsified oil and grease, bacteria and virus, nutrients such as nitrate and phosphate, and heavy metals and organochlorines. Sludge management is a big challenge for waste management authorities. This is mainly due to increasingly stringent sludge reuse and disposal regulations. Therefore, there are a lot of challenges in managing the sludge to make sure that it is sent for reuse at the end of the process. In India, 38000 million liters per day (MLD) sewage generation (2016) is estimated, and approximately 35% of treatment capacity is available nationally, of which more than 50% is in urban areas. In India, the average sludge generation is about 144 kg/MLD (dry basis), with a specific sludge generation of 7.34 kg/capita/year. Complete municipal wastewater treatment would produce ≈ 3.96 million tons of dry sludge annually. Sludge management is a worldwide concern, and various disposal methods have been utilized based on local circumstances. Sludge disposal strategies and environmental repercussions are defined mainly by the issues regarding treatment and disposal (Sludge treatment and disposal accounts for 40-60 % of total plant operation cost), land applications (restricted by pathogens, emerging contaminants, heavy metals, etc.), Incineration (high capital cost, generates ash, discharges heavy metals, CO2 and N2O to the atmosphere), and the landfill (High building, operational and land cost restricted due to emissions and loss of resource). Is sludge only a by-product? Is it feasible to utilize it as a resource? The terms "waste" and "resource" must be defined fully to address these problems. And to do that, "Sludge Characterization" is essential. This report examines the characteristics of sewage sludge and how it may be utilized sustainably. In addition, the report explains how sludge characterization aids in effective sludge management.